I was using spray primer (army painter black) and was doing a jetbike. I look down and it looks rough like sandpaper. I realize the can was just about empty. Now not sure how to fix. Very strange and have not seen it before. Is it something from the bottom of the spray can? What can I do other than dump it in green stuff and try and strip it?

That is typical for spray cans to do that near the end of their life. I don't know what it is but it happened to me plenty. I would stop using my spray cans after they got too low and save it for terrain or bases.

Depending on the shape of the parts that need fixing, you can try microfibre sanding paper. These are used by jewellers to polish metals. The grits are extremely fine, 800, 1200, 1600, 4000, 6000, 8000 etc.; this will help smooth the surface without adding scratches to the plastic or metal model.

After a week in simple green, no love...well, lots of love between the primer and the model, so no divorce would be better wording. So, I took some 500 grit and went at it, got it tolerable and put a new coat on. There is still some texture, but I think I will try to use that to create some damage effect. It is on a jet bike, so maybe rocks or shrapnel blew into it at speed or something.